From 892365ab4d29ed861709ee8611b53587ca2bb75f Mon Sep 17 00:00:00 2001 From: Gerald Schaefer Date: Fri, 24 Feb 2012 18:01:29 +0100 Subject: [S390] memory hotplug: prevent memory zone interleave This fixes a kernel oops with CONFIG_DEBUG_VM triggered by a VM_BUG_ON(bad_range()): kernel BUG at mm/page_alloc.c:748. With memory hotplug on System z, it is possible that the memory online/offline state is preserved over a system restart, e.g. there may be offline memory blocks in ZONE_DMA or ZONE_NORMAL. So far, the offline memory range has always been added to ZONE_MOVABLE during system start, so that it was possible to have ZONE_MOVABLE interleave with ZONE_DMA or ZONE_NORMAL. This patch fixes that by checking for zone overlap before adding memory. Signed-off-by: Gerald Schaefer Reviewed-by: Heiko Carstens Signed-off-by: Martin Schwidefsky --- arch/s390/mm/init.c | 30 ++++++++++++++++++++++++++---- 1 file changed, 26 insertions(+), 4 deletions(-) (limited to 'arch/s390/mm') diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c index 5d633019d8f3..50236610de83 100644 --- a/arch/s390/mm/init.c +++ b/arch/s390/mm/init.c @@ -223,16 +223,38 @@ void free_initrd_mem(unsigned long start, unsigned long end) #ifdef CONFIG_MEMORY_HOTPLUG int arch_add_memory(int nid, u64 start, u64 size) { - struct pglist_data *pgdat; + unsigned long zone_start_pfn, zone_end_pfn, nr_pages; + unsigned long start_pfn = PFN_DOWN(start); + unsigned long size_pages = PFN_DOWN(size); struct zone *zone; int rc; - pgdat = NODE_DATA(nid); - zone = pgdat->node_zones + ZONE_MOVABLE; rc = vmem_add_mapping(start, size); if (rc) return rc; - rc = __add_pages(nid, zone, PFN_DOWN(start), PFN_DOWN(size)); + for_each_zone(zone) { + if (zone_idx(zone) != ZONE_MOVABLE) { + /* Add range within existing zone limits */ + zone_start_pfn = zone->zone_start_pfn; + zone_end_pfn = zone->zone_start_pfn + + zone->spanned_pages; + } else { + /* Add remaining range to ZONE_MOVABLE */ + zone_start_pfn = start_pfn; + zone_end_pfn = start_pfn + size_pages; + } + if (start_pfn < zone_start_pfn || start_pfn >= zone_end_pfn) + continue; + nr_pages = (start_pfn + size_pages > zone_end_pfn) ? + zone_end_pfn - start_pfn : size_pages; + rc = __add_pages(nid, zone, start_pfn, nr_pages); + if (rc) + break; + start_pfn += nr_pages; + size_pages -= nr_pages; + if (!size_pages) + break; + } if (rc) vmem_remove_mapping(start, size); return rc; -- cgit v1.2.3